Sintering Characteristic and Piezoelectric Properties of Lead-free (K_(0.5)Na_(0.5)NbO_3-LiNbO_3 Ceramics

Lead-free (1 - x)(K0.5Na0.5)NbO3-xLiNbO3 piezoelectric ceramics were prepared by a traditional ceramic processing. The sintering characteristic, the microstructure and electrical properties of (K0.5Na0.5)NbO3-LiNbO3 ceramics were investigated. Results show that all specimens exhibit a pure per-ovskite structure and the phase structure at room temperature transforms from orthorhombic to tetragonal with the increase of LiNbO3.The microstructure of (K0.5Na0.5)NbO3-LiNbO3 ceramics exhibits apparent difference due to different amounts of LiNbO3. The sinterability of (K0.5Na0.5)NbO3-LiNbO3 is improved and the sintering temperature is lower than that of pure KNN ceramics. The (1 - x)(K0.5Na0.5)NbO3-xLiNbO3 (x=0.06) ceramics exhibits an excellent piezoelectric properties with the piezoelectric constant d33, the electromechanical coupling coefficients kp and kt of 205pC/N, 40.3% and 49.8%, respectively.